"Flight of the Butterflies," from SK Films, a Toronto production company, premiered at the Smithsonian Institution's National Museum of Natural History.

Photo: Courtesy Of SK Films

"Flight of the Butterflies," from SK Films, a Toronto production...

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More than a dozen sites on five mountains in Michoacan and Mexico state have been identified as winter homes for monarchs.

Photo: Courtesy Of SK Films

More than a dozen sites on five mountains in Michoacan and Mexico...

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Shooting the 3D film required dozens of workers to transport a great deal of sophisticated equipment into the sanctuaries, some of which you can see here in this photo of the crew at work.

Photo: Courtesy Of SK Films

Shooting the 3D film required dozens of workers to transport a...

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A Monarch takes flight. Monarch offspring fly north in late March, but they never make it back to their ancestral homes. They breed en route and then die, leaving the rest of the journey to a new generation.

Photo: Courtesy Of SK Films

A Monarch takes flight. Monarch offspring fly north in late March,...

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The monarchs that reach Mexico see their off-spring head back to their northern homes in March, but it takes yet another generation to make the return trip to the sanctuaries the following winter.

Photo: Courtesy Of SK Films

The monarchs that reach Mexico see their off-spring head back to...

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One of hundreds of millions of monarchs that migrate to Mexican sanctuaries like the one in the film each year.

Photo: Courtesy Of SK Films

One of hundreds of millions of monarchs that migrate to Mexican...

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Before they were stars: every one of the thousands of butterflies shown in the film got its start as a caterpillar, like the one shown here.

Photo: Courtesy Of SK Films

Before they were stars: every one of the thousands of butterflies...

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The dozens of members of the film's crew - and a helicopter or two - were charged with the task of hauling the extensive equipment required to shoot the film up into the remote mountain sanctuaries.

Photo: Courtesy Of SK Films

The dozens of members of the film's crew - and a helicopter or two...

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The film's hero, Fred Urquhart, is portrayed by Canadian actor Gordon Pinsent, seen here with fellow Canadian Patricia Phillips, who plays his character's wife, Norah Urquhart.

Photo: Courtesy Of SK Films

The film's hero, Fred Urquhart, is portrayed by Canadian actor...

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A closer look at a cluster of Monarch butterflies.

Photo: Courtesy Of SK Films

A closer look at a cluster of Monarch butterflies.

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Millions of monarchs, hundreds of millions in a good year, take wing in Canada and the northern United States in late September, flying up to 100 miles a day to reach their winter homes in mid-November.

Photo: Courtesy Of SK Films

Millions of monarchs, hundreds of millions in a good year, take...

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The film's hero Fred Urquhart devoted 40 years of his life to exploring the amazing journey of monarch butterflies and enlisted thousands of volunteers to help tag and track them. Now more than a dozen sites on five mountains in Michoacan and Mexico state have been identified as winter havens for monarchs.

One of my most memorable experiences in 30 years of traveling in Mexico was a day trip to the El Rosario monarch sanctuary, an aerie at 10,000 feet in eastern Michoacan's mountains. My cousin and I were staying in Morelia in late November, just as the butterfly vanguard was arriving. Organized tours weren't running yet, so we drove several hours to Angangueo, the nearest town. We still had another 1,000 feet to climb on our own two feet.

Fortunately for our sea-level lungs, the switchbacked path offered plenty of benches for frequent rest stops near signs recounting one of Earth's most amazing migrations. Millions of monarchs—hundreds of millions in a good year—take wing in Canada and the northern United States in late September, flying up to 100 miles a day to reach their winter homes in mid-November. Their offspring fly north in late March, but they never make it back to their ancestral homes. They breed en route and then die, leaving the rest of the journey to a new generation. Yet another generation sets out for Mexico the following winter, following their great-grandparents' path with pinpoint accuracy.

The climb seemed endless, and I had almost despaired of ever seeing a monarch when a man on his way back down urged me on with a beatific "Es increíble!" A little farther, we reached a high meadow glowing with yellow flowers that were weighted down by feasting butterflies. All we could do was lie on our backs, looking up at millions of translucent orange and black wings sparking against a deep blue sky. Those were the two most psychedelic hours of my life — and I say this as a child of the '60s.

Flight of the Butterflies in 3D

It is one of the tragedies of the protracted drug war that Michoacan, a beautiful slice of authentic Mexico that has always been inexplicably overlooked by U.S. tourists, is one of the hot spots that visitors are warned away from. Put the monarch sanctuary on your bucket list anyway, even if you have to wait awhile for the all-clear signal.

In the meantime, SK Films, a Toronto production company, has done the world a great favor by making "Flight of the Butterflies," a 3D movie for IMAX theaters that opens in limited release Saturday. It premiered this week at the Smithsonian Institution's National Museum of Natural History with Mexican President Felipe Calderon, an ardent butterfly advocate, in attendance.

The film follows the monarchs' 2,500-mile journey, weaving a stunning natural history documentary with a stirring detective story. The hero is Fred Urquhart, a tenacious scientist who as a small boy had fantasized about where the butterflies went every winter. He devoted 40 years of his life to uncovering the mysteries surrounding their amazing journey and enlisted thousands of volunteers—his "citizen scientists"—to help tag and track the insects. Their efforts finally paid off in 1976, and now more than a dozen sites on five mountains in Michoacan and Mexico state have been identified as winter homes for monarchs.

On the way to that discovery, Urquhart also learned that it takes two to three generations of butterflies to migrate north from Mexico through the United States to Canada, and one "super generation" to complete the migration back to Mexico.

This film was a monumental undertaking. Making a 3D movie isn't as simple as climbing up the mountain slopes with a minicam: It took dozens of workers and the occasional helicopter to move equipment the size of school buses into the mountains. Said equipment included MRI and micro CT scans that captured close-up views showing the monarchs' evolution from egg to caterpillar to pupa to butterfly like no one has ever seen before.

The first of Urquhart's citizen scientists were American Ken Brugger and his Mexican wife, Catalina Aguado. Urquhart and Brugger are both dead; Aguado served as an advisor and accompanied the film production team to the monarch filming site in the mountains west of Mexico City, where they worked for two years to find the butterflies' wintering grounds. Canadian actors Gordon Pinsent and Patricia Phillips portray Urquhart and his wife, Norah (also Canadians).

The movie will roll out all over the world throughout 2013. Unfortunately, Northern California isn't on the schedule until next year (San Jose in spring; Sacramento late summer), though it opens in San Diego at the Reuben H. Fleet Science Center Oct. 5 and at Seattle's Pacific Science Center Oct. 19. If I don't get impatient and journey north or south before then, I'll be in San Jose come spring to let the magic of 3D surround me with golden butterflies once again.